ChangeDetection.io is an open source monitoring tool that tracks changes to websites and sends alerts when selected content is added, removed, or modified. Users can monitor government pages, public records portals, policy documents, court information, regulatory notices, news pages, organizational websites, product listings, data feeds, and other online resources that may change over time.
The platform regularly checks selected web pages and records new versions when it detects a change. Users can compare saved versions to identify exactly what text was added, deleted, or revised. The history feature includes timestamped snapshots and several comparison formats, including line, word, character, and JSON comparisons. Monitoring begins after a page is added, so the platform does not automatically recover changes that occurred before the watch was created.
ChangeDetection.io can monitor an entire page or focus on specific information. Users can select individual page elements and apply CSS, XPath, JSONPath, jq, keyword, trigger text, and ignore text filters. These controls can reduce unnecessary alerts caused by menus, timestamps, advertisements, rotating images, and other frequently changing page elements.
The Browser Steps feature can interact with more complex websites. It can perform searches, enter information into fields, select buttons, navigate forms, and access certain pages that require a login. This feature may help researchers monitor databases, search result pages, interactive government portals, and JavaScript based websites that cannot be tracked through a simple page request.
Users can receive notifications through email, Discord, Slack, Telegram, Matrix, Microsoft Office 365, Rocket.Chat, NTFY, custom application programming interfaces, and many other services. Alerts can be configured for individual pages or organized into groups. Conditional actions can also limit notifications to changes involving a particular keyword, price, value, or other defined condition.
ChangeDetection.io offers both a hosted subscription service and free open source software that can be installed on a private server. The self hosted version can be deployed with Docker, Python, Windows, Linux, Raspberry Pi, and other supported environments. Self hosting may appeal to researchers and organizations that want greater control over their monitoring data, infrastructure, access settings, and stored page history.
The platform also includes an application programming interface for creating and managing watches, retrieving page history, comparing snapshots, organizing monitored pages, importing lists of URLs, and managing notifications. These features can support larger research projects, automated documentation systems, compliance monitoring, and collaborative investigative workflows.
For civic researchers, ChangeDetection.io can help document changes to agency websites, enforcement policies, public meeting notices, election information, government reports, official biographies, procurement pages, press releases, public health guidance, and regulatory materials. It can also alert users when an agency removes a document, changes important language, publishes a new report, or updates a public deadline.
The tool may be especially useful for journalists, watchdog organizations, legal researchers, archivists, policy analysts, advocacy groups, community organizers, and residents monitoring public institutions. A documented page change can identify what changed and when the platform detected it. However, the change record alone does not establish why the change occurred or whether it was improper. Important findings should be preserved and confirmed through official records, archived copies, metadata, public records requests, or direct communication with the organization responsible for the page.
Users should configure monitoring responsibly and follow applicable laws, website terms, privacy requirements, and access restrictions. Sensitive login credentials and private information require additional care, especially when using a hosted service or monitoring pages that are not publicly accessible.
Services and Resources
ChangeDetection.io provides automatic website monitoring, timestamped page history, text comparison, keyword alerts, visual element selection, browser automation, JSON monitoring, scheduling, conditional notifications, website restock tracking, application programming interface access, and integrations with numerous communication platforms.
The website also provides tutorials explaining how to monitor keywords, policy changes, software releases, website history, regulatory information, interactive forms, pages behind logins, JSON feeds, and other changing online content.
Who This Resource Helps
This resource may help investigative journalists, civic researchers, archivists, attorneys, nonprofit organizations, policy analysts, government watchdogs, election monitors, community advocates, compliance professionals, and residents who need to follow changes across public websites.
It may also support researchers investigating deleted government pages, revised public policies, changing enforcement language, altered official statements, new court information, updated meeting notices, procurement changes, regulatory developments, and modifications to public datasets.